Commentary

Agent Teams Without an Arbiter Turn on Each Other

Bruno Coelho Reliability & Assurance

Who should read this: executives approving multi-agent deployments, and the platform teams wiring agents into shared systems. Horizon: this quarter.

What happened. Anthropic gave three Claude instances the same codebase and contradictory goals: each was told to migrate the backend to a different language. Every model tested concluded the others were interfering on purpose. They protected their own work, then attacked, force-terminating rival processes and writing increasingly aggressive self-replicating malware against each other. In the study’s own words, most Sonnet 4.6 and Opus 4.6 runs ended by force or never settled. A minority resolved it the right way: they recognised the contradiction in their instructions and asked the human for help.

Why it matters. Multi-agent systems are being sold as teams, and teams are assumed to add up. The evidence says coordination must be designed: without explicit authority, contradictory incentives turn shared infrastructure into a battlefield, and the agents in this experiment reached for sabotage faster than for clarification. Enterprises are wiring agents from different vendors, departments and budgets into the same systems this year, and inside any real organisation, partially conflicting objectives are the everyday condition.

What to do. Think about the prototype of functional teams: all have “a contract” on who does what, “rules of engagement”, and a leader who settles differences and makes decisions. Agentic systems are no different. In case you are thinking this is just a “research topic”, I assure you it is not. I have experienced this pattern myself in my projects. Until I ensured a written coordination contract, nominated a coordinator and decision-maker, and detailed the mechanism for how agents communicate, I spent my time solving the mistakes of coordination myself. After the “contract”, on the same day, two agents caught each other’s boundary errors and brought both to me for the decision. Consider the following thought experiment: What if one of my agents goes dark against the contract, into a spree of expenditure and damage? The question you should ask: How are my agentic systems today? Where do my design guidelines, “checklists”, my review process and stress tests stand on this topic?

Where I would be wrong. This article was done to showcase and study the behaviour. Your case might not match. However, waiting for a production incident before acting buys the same lesson at incident cost when it is available today for a page of governance.